Which Color Space in Unity provides clear differentiation between light and dark areas with direct light?

The correct choice is Linear, as this color space is designed to provide a more physically accurate representation of light. In a linear color space, color values are treated in a way that corresponds better to how light interacts in the real world. This means that light and dark areas are represented with greater clarity, allowing for finer distinctions between them when direct light is applied.

In linear color space, the blending of colors and the output of lighting calculations are calculated based on light intensity, leading to optimal light behaviors and effects such as accurate shading, reflections, and highlights. This is particularly important in game development, where realistic lighting can dramatically affect the mood and realism of the environment.

Other color spaces, such as Gamma, are based on nonlinear transformations that can lead to issues with how light is interpreted. RGB and CMYK, while essential in different contexts (like screen displays and printing respectively), do not inherently provide the same benefits for differentiating light and dark areas in 3D rendering as linear space does. Thus, when aiming for realistic lighting in Unity, the linear color space is the most effective choice.